Process of toughening or annealing steel, iron, and other metals.



No. 843,563. PATENTED FEB. 5, 1907. W. F. L. FRITH.

' PROCESS OF TOUGHENING 0R ANNBALING STEEL, IRON, AND OTHER METALS.

APPLICATION FILED FEB. 24, 1902.

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UNITED AT PAEN IQ.

WILLIAM F. L. FREE, OF LONDON, ENGLAND.

PROCESS OF IOUGHENING 0R ANNEALING STEEL. IRON, Arc OTHER METALS.

Specification of Letters Patent.

Patented Feb. 5, 1907.

Application filed February 24, 1902. Serial No. 95.468.

To all whom it may concern:

Be it known that I, WILLIAM FREDERICK LOWNDES FRITH, a citizen of GreatBritain, residing at 24 Rood Lane Chambers, Rood Lane, London, E. 0.,England, have invented a new and useful Improved Process for Tough eningor Annealing Steel, Iron, and other Metals, of which the following is aspecification.

This invention relates to an improved process for treating steel, iron,and other metals, so as to give greater tenacity and elasticity and soas to render the metals treated highly resistant *to the penetration ofprojectiles and to the corrosive action of sea-water and the weather.

The invention consists generally in heating the metal to be treatedwithin a closed receptacle and subjecting the metal to fluid-pressure,such as the pressure of mercurial-vapor, and allowing the metal treatedto slowly cool While in the receptacle, an electric current beingpreferably passed through the [metal treated while in the receptacle.

The accorn anying drawing illustrates diagrammaticaly insectionalelevation apparaetus employed to carry the invention into effect.

In carrying the invention into efiect I referably arrange the receptaclea upon W eels c, by means of which it may be conveniently run into thefurnace b. j I provide the receptacle a of any suitable form and with acover d, which may be tightl bolted into position, so as to bepressure-tig t.

The receptacle 0. is provided with an outlet by means of which the airwithin the'receptacle a may find egress. An outlet-pipe e communicateswith the outlet and is carried through the walls of the furnace and hasfor convenience a tap, by means of which such outlet-pi e may be closed.The receptacle may furt ermore be provided' at its opposite ends orsides with electrodesf, by means of which current may be caused to passthrough the metal plates or bodies 9 to be treated. The electrodes f mayconveniently be arranged within non-conducting bosses or bus es 72.,secured within the ends or sides of the'recepta'cle, and the electrodesmay be oapable of adjustment therein.

The furnace b itself may be of any convenient kind and may derive itsheat from any suitable source (not shownin the drawin and may beprovided with a sliding door 1, cIosing an aperture through which thereceptacle covers d are placed in position and screwed down tightly. Thereceptacle is then passed into the furnace b. and heated for abouttwelve hours to about 1,000 Fahrenheit. The receptacle is then withdrawnand its contents are allowed to cool slowly. The

duration of the heating and cooling periods vary with the differentsizes and compositions of the articles to be treated. During heating orcooling a current may be sent through the apparatus, either constantlyor intermittently, the quantity. depending on the'size of the lates orbodies to be treated and on the c emical constitution of' the metal. Asthe rece tacle becomes heated the valve on the out etpipe is opened, soas to. allow the heated air to iind egress, and the valve is maintainedopen until the vapor of mercury condenses and drops from theoutlet-pipe. When thus an indication is afforded that the receptacle isfilled with mercurial.

vapofl the valve' is closed, It will thus be seen that I do not employ auniform r'essure of gas in the heating and cooling, ut that the pressuredepends wholly upon the temperature to which the metal is subjectedunder treatment.

Instead of mercurial vapor air, steam, or other vapor or gas underpressure may be employed for the same purpose, and instead of providinga portable receptacle a fixed chamber may be provided in connection witha suitable furnace or other source of heat.

The tenacity, elasticity, and toughness of plates or bodies treatedaccordingto the invention are increased, and they are rendered highlyresistant to the penetration of projectiles and to the corrosive actionof sea-water or' the weather.

The process is not only applicable .for

treating steel, but also iron and other metals,

IlO

What I claim as new, and desire to secure by Letters Patent, is

1. A process of treating steel and other metals, comprising a subjectionof the metal to heat and to direct action of metallic vapor underpressure in a closedreceptacle, said pressure varying with andcorresponding to the temperature to which the metal is subj ected.

2. A process of treating steel and other metals, com rising a subjectionof the metal to heat an to direct action of mercuric vapor underpressure in a closed receptacle, said pressure varying with andcorrespondin to the temperature to which the metal is su% jecte:l.

3. A process of treating steel and other metals com rising a successiveheating and cooling of t e metal under pressure by the direct action ofmetallic vapor in a closed receptacle, said pressure varying with andcorresponding to the temperature to which the metal is subjected.

4. A process of treating steel or other metals comprising a successiveheating and cooling of the metal under pressure by the direct action ofmercuric vapor in a closed receptacle, said pressure varying with andcorresponding'to the temperature to which the metal is subjected.

5. A process of treating steel and other metals comprising a subjectionof the metal to heat and to the direct action of vapor under pressure ina closed receptacle, said pressure corresponding to the temperature towhich the metal is subjected, While an electric current is being passedthrough the metal.

6. A process of treating steel or other metals comprising a subjectionof the metal to heat and to the direct action of gaseous vapor in aclosed receptacle, said pressure corresponding to the tem erature toWhich the metal is subjected, an the passing of an electric currentthrough the metal while heated.

7. A process of treating steel or other metals, comprising a subjectionof the metal to heat ancl'to direct action of mercurlc vapor in a closedreceptacle, said pressure corre-

